Announcement

Collapse
No announcement yet.

Oil passages and oil specs

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Oil passages and oil specs

    Another thread on oil additives has prompted me to inquire about this subject. In some of my older engines, I have increased the weight of the oil I am using from 30 WT to 20-50WT. About a year or so ago, I decided that I probably should do the same on my 334,000+ Nissan V6 truck. However, a friend, who has been in the parts supply business for about 40 years, discouraged me from doing this. He said that in some of these more modern engines, the oil passages are too small to allow sufficient flow for heavier viscosity oils. He said the oil could "Pool" in the valve covers and starve other areas of the engine. Since I really have no problem with the engine, I decided not to change to the heavier oil. What about our Studebaker engines? I have heard of problems caused by restricted flow due to sludge or junk in the oil passages, but not because of any engineering limitations. I know that the forum has a lot of "Back Yard" (Shade Tree) mechanics, but some of you guys eat, breathe, sleep, and earn a living doing this stuff. So...the question is ...At what point does heavier viscosity oil clash with the law of diminishing returns?

    John Clary
    Greer, SC

    Life... is what happens as you are making plans.
    SDC member since 1975
    John Clary
    Greer, SC

    SDC member since 1975

  • #2

    I heard an analogy once that made a lot of sense. "In regards to oil weights, the higher the viscosity, the higher the resistance to flow".

    I don't know what you're using in the truck, but I'd stick with it and just change it more often


    Bob Johnstone
    www.studebaker-info.org

    64 GT Hawk
    55 President State Sedan
    70 Avanti (R3)
    64 GT Hawk (K7)
    1970 Avanti (R3)

    Comment


    • #3
      Modern engines are built with much closer tolerances than they used to be so they will run quite happily on thinner grade oils. Many Ford and Hondas specify 5W-20 or even 0W-20 oils for year around driving. Using too high a weight motor oil isn't helping anything unless you're experiencing a high rate of usage and there are no leaks.




      Poet...Mystic...Soldier of Fortune. As always...self-absorbed, adversarial, cocky and in general a malcontent.
      Poet...Mystic...Soldier of Fortune. As always...self-absorbed, adversarial, cocky and in general a malcontent.

      Comment


      • #4
        10W-30 oil in your Nissan truck should be fine. 20W-50 was formulated for older engines with more bearing clearance than the newer engines. My personal preference in Studebaker engines is 15W-40 Chevron Delo 400 or Shell Rotella T which is an oil meant for heavy duty diesel engines with an additive package that is formulated for use in gasoline engines. The diesel oils also have added anti wear addives, so no other additives are needed. Bud

        Comment


        • #5
          Id stick with a 10W40 or any 40WT multi viscosity. The reason for most using 20W50's was because many would shear out 1/3rd into the life of the oil thus you have a 40WT anyway. That's why many but not all air cooled motorcycle engines still recommend 20W50. I make my decision based on oil consumption. If you are not using any more oil with a 20W50 then you should go back to the 10W40 or 15W40.
          20W50's will also decrease performance while increasing heat and wear in many cases.
          Yes - dont go above 10W30 in the Nissan. I do know from prior service bullitins that Nissans do need heavier viscosities in the differential though. 75W110 or 75W140. Amsoil AMO 10W40 is 1450 PPM of ZDDP and the noticeable smoothness in the engine will astonish you. That and the diesel 15W40 AME both meet the prior diesel CI4 everyone looks for. Most current Diesel oils on the shelf ate CJ4 which do not contain the same level of detergents and antiwear additives engines prior to 1990 need.

          Just wanting to drive my Stude in the black hills.

          Comment

          Working...
          X